diff --git a/planetstack/core/models/__init__.py b/planetstack/core/models/__init__.py
index ac12370..b453a14 100644
--- a/planetstack/core/models/__init__.py
+++ b/planetstack/core/models/__init__.py
@@ -28,3 +28,4 @@
 from .reservation import ReservedResource
 from .reservation import Reservation
 from .network import Network, NetworkParameterType, NetworkParameter, NetworkSliver, NetworkTemplate, Router, NetworkSlice
+from .billing import Account, Invoice, Charge, UsableObject, Payment